Transparent paper and process of making the same.



80 knit, coarse-fihere composition of the ma- ENYELOPE COMPANY, OF

To all whom it mag concern:

Be it known that I, WILLARD E. SwIr'r,-a citizen of the United States, residing, at Worcester, in the county of Worcester and v Commonwealth of Massachusetts, have invented a new and useful Improvement in Transparent Paper and Processes of Making the Same, of which the following is a specification.

The present invention relates to processes of treating paper to render the same transparent and, in general, has reference to the treatment of paper with oleaginous substances such as varnish, liquids having transparent matter in solution, or the like, to accomplish the desired result.

As heretofore practised, processes of this class,;'contem latin the application oi a transparentiizing su stance indliquifd "form to opaque, or semi-opaque, gra es 0 paper, have attained the desired efi ect b reason of the ermeation of the fibers of t e paper by suc liquid, the, degree of transparency attained being measured by the completeness of such permeation or absorption, which is oftentimes assisted by the subjection of the coated surface to the action of a fluid, such as air, under pressure. The adaptabiiity of most commercial grades of paper to such treatment, by reason of the looselyteria-l and the villous, nap-like character of the surface thereof, is well recognized; it

course, in di erentgrades of paper, may

is apparent also that the best results in such processes are secured by the use of liquids havin the property of drying very.

slowly, in or er that the resistance pat the material to ermeation, which varies, at

be overcome, and also in order that suiii- I cient time as the complete saturation of the paper by liquid may he afiorded.

such prior processes, the liquid passes completely -throu%h the paper, from one surface to the ot er'; the action is essentially one of permeation, and as a sense: .quence', the greater portion, of the liquid till is completely removed andisolated from the drying action of the atmosphere, the'eva oration of the liquid is practically never ceinple'ted, and the paper'thus treated, while f possessing a certain limlted degree of trans parency, invariably is of an oily er sticlry nature on both sides, never thoroughly dry, andinherently unsuited to any use which.

a a a. swim, or woncns'rmmnonnsn'rrs, nssran'on 'ro sramerrnrn, massaonusnrrs, a coo-men or rennin rerun; nun Gasser manure is sarrn.

Spcoifleatioaof Letters lE'atent. Patented App, 29, 191L239, Application filed March 1, 1915. serial No. 11,219. I I

involves the application of adhesive -'or glue papier which is generally used by envelop ers in the manufacture of the so called Outlook envelops or envelops having av transparent panel to disclose an address on the inclosure, and which is commercially limown as glacine paper; and the said invention, in contradistinction to the al ready known processes above referred to, is more perfectly carried out by the use of liquids which have the property of drying very quickly.

As 1s well knownfglacine paper difiers 7 widely in composition and texture from. ordinary opa ue or semi-opaque paper; the texture of g acine paper is close-knit, by reason of the preponderance of cellulose mattier in the composition thereof, and, moreover,

said paper present a smooth, hard and;

practically impenetrable'surface, quite una like the nap-like surface of ordinary paper. The cellulose character of the material gives it its transparency quality; ho'wever,.I have discovered that the degree of such trans parency may be very considerably increased by the treatment of one or both surfaces with a liquid, such. as a varnish, or other zsnbstantially transparent liquid havingres- Wt inous or other transparent matter in solution, z

In carryin of the glacine paper. Such app ication may be made with a brush, or by th use of a ie or roller coated with the l uid or I hy any otherwell-known means the properli of dryreferably, a solution havin mg quickly is used M; I do n t wish to ee-myseif to the use at s d a solu--- tion, since it is manifest that thd character of. the paper itseli, by reason Loft its impenetrahihty, is conducive to the rapid drythe ing of the -iquid, since said liquid lies on the surface of the paper in ie-lilli iil film, oernpietely exposed to the evaporative action out the air,

lit is found that the transparency of the 0 is only to certain grades of paper, 6

out my invention, such a a 'i a liquid is applied by any suitable means, in

a thin coating over one or looth s riaces paper is greatly increased by such treatthinness of the paper, the treatment o one' surface of the same, in the manner above described, has absolutely no 'efiect upon the reverse surface; so that, while increasin the transparency of the paper in marke degree, such treatment of one surface leaves the paper suitable for the application of glue or adhesive to the other surface, for the purpose of attaching the same to various articles.

I am aware that it has been proposed heretofore to treat various grades of opaque paper with an oleaginous substance in order to render the same transparent, and l make no clalm to such a process or operatlon. In

such prior processes the desired result is obtained wholly b the absorption of the liquid by the fibers o the paper, the latter being readily susceptible to rapid and complete permeation. My rocess is concerned with the treatment 0 paper of a particular variety, the characteristic feature of which is its non-fibrous structure, and its ability to resist permeation by any liquid; to promote this action as above described, I preferably employ .a liquid which is quick drying, in order to avoid any possibility of permeation, which action would destroy the efiicacy of my process. v

I claim,

' 1. A trans arent paper formed by applyer ing rapidly rying transparent liquid having .resinous matter in solution to the 'surface of a s'emitransparent nonabsorbent paper having a hard smooth surface.

2. The herein described process of treating a semitransparent nonabsorbent paper having a hard smooth surface by the application theretoof a rapidly drying transarent liquid having resmous matter 1n soution.

Dated this th day of February 1915. WILLARD E. SWIFT. Witnesses:

PENELOPE CoMnERBAoH, Nam WHALEN. 

